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Re: [Qemu-devel] [PATCH v1 7/7] target-arm: Call the pmccntr_sync functi
From: |
Alistair Francis |
Subject: |
Re: [Qemu-devel] [PATCH v1 7/7] target-arm: Call the pmccntr_sync function when swapping ELs |
Date: |
Wed, 25 Jun 2014 08:39:15 +1000 |
On Wed, Jun 25, 2014 at 1:55 AM, Christopher Covington
<address@hidden> wrote:
> On 06/23/2014 09:12 PM, Alistair Francis wrote:
>> Call the new pmccntr_sync() function when there is a possibility
>> of swapping ELs (I.E. when there is an exception)
>>
>> Signed-off-by: Alistair Francis <address@hidden>
>> ---
>>
>> target-arm/helper-a64.c | 5 +++++
>> target-arm/helper.c | 7 +++++++
>> target-arm/op_helper.c | 6 ++++++
>> 3 files changed, 18 insertions(+), 0 deletions(-)
>>
>> diff --git a/target-arm/helper-a64.c b/target-arm/helper-a64.c
>> index 2b4ce6a..b61174f 100644
>> --- a/target-arm/helper-a64.c
>> +++ b/target-arm/helper-a64.c
>> @@ -446,6 +446,8 @@ void aarch64_cpu_do_interrupt(CPUState *cs)
>> target_ulong addr = env->cp15.vbar_el[1];
>> int i;
>>
>> + pmccntr_sync(env);
>> +
>> if (arm_current_pl(env) == 0) {
>> if (env->aarch64) {
>> addr += 0x400;
>> @@ -484,6 +486,7 @@ void aarch64_cpu_do_interrupt(CPUState *cs)
>> addr += 0x100;
>> break;
>> default:
>> + pmccntr_sync(env);
>> cpu_abort(cs, "Unhandled exception 0x%x\n", cs->exception_index);
>> }
>>
>> @@ -511,4 +514,6 @@ void aarch64_cpu_do_interrupt(CPUState *cs)
>>
>> env->pc = addr;
>> cs->interrupt_request |= CPU_INTERRUPT_EXITTB;
>> +
>> + pmccntr_sync(env);
>> }
>
> The double calls seem unwieldy. I think it could be made into a single
> function call if there was access, perhaps as a second parameter or maybe as a
> static variable, to both the previous and current state so the function could
> tell whether there is no transition, enable->disable, or disable->enable.
>
The problem with a parameter is that the state of the enabled register needs
to be saved at the start of any code that will enable/disable the register. So
it ends up being just as messy.
Static variables won't work if there are multiple CPUs. I guess an
array of statics
could work, but I don't like that method
I feel that just calling the function twice ends up being neat and
works pretty well
> Christopher
>
> --
> Employee of Qualcomm Innovation Center, Inc.
> Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum,
> hosted by the Linux Foundation.
>
Re: [Qemu-devel] [PATCH v1 0/7] target-arm: Extend PMCCNTR for ARMv8, Peter Maydell, 2014/06/26